Not only is the 1,200-mile-wide (1,931-kilometer-wide) sanctuary home to extensive coral reefs, lagoons, and deep-water mountains called seamounts, it's also the place where native Hawaiians believe life originates and where spirits return after death, according to the World Heritage website.

Regarding the site's mixed status, "it's more important that we look for that in every site—to look at cultural uniqueness and the interplay of humans as part of nature," said Francis, also a vice president of research, conservation, and exploration for the National Geographic Society, which owns National Geographic News.

—Christine Dell'Amore

Photograph courtesy Claire Fackler, NOAA

La Réunion National Park

With its "remarkable and visually appealing" landscape, La Réunion National Park—part of France's Réunion Island in the southwest Indian Ocean—has earned its place as a new natural World Heritage site.

The 247,000-acre (100,000-hectare) region features a rugged terrain of pitons, or sharp mountain peaks; cirques, or steep-walled basins; and remparts, or ridges of unconsolidated rock fragments, earth, or other debris. The mountains also boast subtropical rain forests, cloud forests, and open shrublands called heaths.

"La Réunion contains an impressive mosaic of dramatic landscapes and very valuable ecosystems, and also serves as a last refuge for the many threatened and endangered species," Tim Badman, head of the IUCN World Heritage Programme, said in a statement.

A person crosses over a waterfall in Russia's Putorana Plateau, a place of "striking natural beauty" that includes more than 25,000 fjord-like lakes; dozens of deep canyons, rivers and creeks; and thousands of waterfalls, according to the UNESCO World Heritage website.

The Arctic region of diverse tundra ecosystems—which features a rare reindeer-migration route—has been added to the 2010 list of natural World Heritage sites. (See pictures of tundra landscapes.)

"The combination of extraordinary landscape diversity, remoteness, and naturalness makes the Putorana Plateau one of the truly wild places remaining in the Arctic at a time of increasing pressure on this fascinating region," IUCN's Badman said.

For instance, many Arctic ecosystems are changing rapidly due to rising temperatures from climate change, he said. (See Arctic climate change photos.)

Photograph by Randy Olson, National Geographic

Sri Lanka's Central Highlands

The forests of Sri Lanka's central highlands (pictured, a forest tea plantation) boast an "extraordinary range" of animals and plants that helped the region earn designation on this year's World Heritage list, according to the UNESCO website.

Several endangered species such as the western purple-faced langur, the Horton Plains slender loris, and the Sri Lankan leopard roam these forests up to 8,000 feet (2,500 meters).

A man stands among giant clam beds in Kiribati's Phoenix Islands Protected Area, the largest designated marine protected area and one of five new natural sites added to the UNESCO World Heritage list. Kirabati, a tiny country in the central Pacific (see map), is made up of the Gilbert Islands, Line Islands, and Phoenix Islands.

The sanctuary is one of the planet's healthiest coral archipelagos—or large group of islands—hosting 800 species of animals, including 500 species of fish and 18 species of marine mammals.

The islands' "exceptionally healthy populations of fish, turtles, and its bleaching-resistant corals deserve the highest degree of protection," Tilman Jaeger, World Heritage Project Management Officer for the International Union for Conservation of Nature (IUCN), said in a statement.

"Continued international support to Kiribati for the management of the site will be vital to guarantee its conservation."

Photograph by Paul Nicklen, National Geographic

Danxia Range

"Spectacular" red cliffs make up China's Danxia landscape (pictured, a cliff in Red Stone Park), one of UNESCO's new natural World Heritage sites.

A range of erosional landforms—such as natural pillars, towers, ravines, valleys, and waterfalls—are found in southwest China. The evergreen forests also host many species of animals and plants, 400 of which are considered rare or threatened, according to the World Heritage website.

Photograph by Raymond Gehman, National Geographic

Everglades National Park

An eastern diamondback rattlesnake moves across a mangrove tree in Florida's Everglades National Park. In addition to the new natural sites added to the World Heritage list, UNESCO inscribed two natural sites to its List of World Heritage in Danger, including the Everglades, which has suffered due to "serious and continuing degradation" of its ecosystem, according to the World Heritage website.

Human activities have reduced natural water flows into the Western Hemisphere's largest mangrove ecosystem by 60 percent, the website says. And runoff pollutants such as nitrogen and phosphorus are creating algal blooms that could harm marine species, including the endangered manatee. (See Everglades pictures.)

The Everglades has been in peril before: The "river of grass" was first placed on UNESCO's danger list in 1993, following damage caused by Hurricane Andrew. The park was taken off the list in 2007 thanks to renewed efforts to restore the ecosystem—but those efforts have since proved less than successful.

Illegal logging, poaching of rare lemurs, and other environmental damage in the species-rich country has occurred in the midst of ongoing political turmoil, according to the nonprofit Conservation International.

"This has also shattered the nation's tourist industry, which was a key driver in its economic development, and is pushing many species that exist nowhere else on Earth to the brink of extinction," Russell Mittermeier, president of Conservation International and IUCN vice-chair, said in a statement.

"Hopefully," Mittermeier said, "adding this incredibly important area to the UNESCO Danger List will make the international community sit up and take notice of what is happening and take serious steps to stop the destruction of Madagascar's incredible natural resources."